如何将func_closure条目映射到变量名? [英] How to map func_closure entries to variable names?
问题描述
我在此函数中创建了一个lambda对象:
I have a lambda object that is created in this function:
def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
self.record(lambda s:
s.add_url_rule(rule, endpoint, view_func, **options))
使用lambda函数对象的 func_closure
我可以访问lambda函数的闭包范围:
Using func_closure
of the lambda function object I can access the closure scope of the lambda function:
(<cell at 0x3eb89f0: str object at 0x2fb4378>,
<cell at 0x3eb8a28: function object at 0x3cb3a28>,
<cell at 0x3eb8a60: str object at 0x3ebd090>,
<cell at 0x3eb8b08: dict object at 0x3016ec0>)
仔细研究一下(在每个 cell
的 cell_contents
属性中对象)显示以下内容:
A closer look (at the cell_contents
attribute of each cell
object) shows me this:
>>> [c.cell_contents for c in func.func_closure]
['categoryDisplay',
<function indico.web.flask.util.RHCategoryDisplay>,
'/<categId>/',
{}]
该lambda函数是通过以下调用创建的:
That lambda function was created by this call:
add_url_rule('/<categId>/', 'categoryDisplay', rh_as_view(RHCategoryDisplay))
如您所见,该顺序与函数的参数顺序或在lambda中使用参数的顺序不匹配。虽然我可以根据其类型/内容轻松地确定哪个元素是什么,但我想以一种更简洁的方式进行操作。
As you can see, the order does not match the argument order of the function or the order in which the arguments are used inside the lambda. While I could easily find out which element is what based on its type/content, I'd like to do it in a cleaner way.
所以我的问题是:如何我可以将其与它们的原始变量名称(或至少在函数参数的情况下为位置)相关联吗?
So my question is: How can I associate it with their original variable names (or at least positions in case of function arguments)?
推荐答案
已创建闭包通过 LOAD_CLOSURE
字节码,按其字节码的排序顺序:
The closures are created by the LOAD_CLOSURE
bytecode, in the same order as their bytecodes are ordered:
>>> dis.dis(add_url_rule)
2 0 LOAD_FAST 0 (self)
3 LOAD_ATTR 0 (record)
6 LOAD_CLOSURE 0 (endpoint)
9 LOAD_CLOSURE 1 (options)
12 LOAD_CLOSURE 2 (rule)
15 LOAD_CLOSURE 3 (view_func)
18 BUILD_TUPLE 4
21 LOAD_CONST 1 (<code object <lambda> at 0x10faec530, file "<stdin>", line 2>)
24 MAKE_CLOSURE 0
27 CALL_FUNCTION 1
30 POP_TOP
31 LOAD_CONST 0 (None)
34 RETURN_VALUE
因此顺序是在编译时由 compiler_make_closure()
;此函数使用 func.func_code.co_freevars
元组作为指南,该列以相同顺序列出了闭包。
so the order is determined at compile time, by compiler_make_closure()
; this function uses the func.func_code.co_freevars
tuple as a guide, which lists the closures in the same order.
func.func_code.co_freevars
在 makecode
,并且元组是从python字典的键生成的,因此顺序是相反的任意的,与词典一样。如果您好奇,可以在 compiler_enter_scope()
,使用 dictbytype()
实用程序功能来自编译器符号表中命名的所有自由变量,本身就是python字典。
func.func_code.co_freevars
is set when creating a code object in makecode
, and the tuple is generated from the keys of a python dictionary, so the order is otherwise arbitrary, as common for dictionaries. If you are curious, the dict is built in compiler_enter_scope()
, using the dictbytype()
utility function from all the free variables named in the compiler symbol table, itself a python dictionary.
因此,关闭的顺序确实是任意的(哈希表已排序),并且您将使用 func.func_code.co_freevars
元组(可以看作是编译器处理字典键的顺序的记录)以将名称附加到闭包上:
So, the order of the closures is indeed arbitrary (hash table ordered), and you'd use the func.func_code.co_freevars
tuple (which can be seen as a record of the order the compiler processed the dictionary keys) to attach names to the closures:
dict(zip(func.func_code.co_freevars, (c.cell_contents for c in func.func_closure)))
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